Article Cite This: Mol. Pharmaceutics 2018, 15, 3545−3556
pubs.acs.org/molecularpharmaceutics
Microneedle-Mediated Transdermal Delivery of Bevacizumab Aaron J. Courtenay, Maelíosa T. C. McCrudden, Kathryn J. McAvoy, Helen O. McCarthy, and Ryan F. Donnelly*
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School of Pharmacy, Queen’s University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, U.K.
ABSTRACT: Bevacizumab is a recombinant humanized monoclonal antibody used clinically as a combination chemotherapeutic. Antibody therapeutics are usually formulated as parenteral injections, owing to their low oral bioavailability. Microneedle technology provides a transdermal alternative for drug-delivery using micron-scale needle structures to penetrate directly through the stratum corneum into the dermal interstitium. This study describes the design, formulation, and in vitro characterization of both dissolving and hydrogel-forming microneedle array platforms for transdermal delivery of bevacizumab. Bevacizumab recovery and transdermal permeation studies were conducted and analyzed using bevacizumab specific ELISA. Prototype microneedle-patches were tested in vivo in Sprague−Dawley rats with serum, exterior lumbar and axial lymph nodes, spleen, and skin tissue concentrations of bevacizumab reported. This work represents the first example of high dose transdermal delivery of an antibody therapeutic in vivo using dissolving and hydrogel-forming microneedle platforms. Basic pharmacokinetic parameters are described including hydrogel-forming microneedles: Cmax 358.2 ± 100.4 ng/mL, Tmax 48 h, AUC 44357 ± 4540, and Css 942 ± 95 ng/mL, highlighting the potential for these devices to provide sustained delivery of antibody therapeutics to the lymph and systemic circulation. Targeted delivery of chemotherapeutic agents to the lymphatic system by MN technology may provide new treatment options for cancer metastases. KEYWORDS: microneedle, bevacizumab, transdermal, hydrogel-forming, dissolving
1. INTRODUCTION The use of biotherapeutic agents has increased rapidly in the past 10 years to become a mainstream treatment option for many diseases, such as cancer.1 Proteins, peptides, virus-like particles, and antibody therapies have progressed to such an extent that they can facilitate efficacious treatment of diseases previously not effectively managed by small molecule drugs. Bevacizumab (BEV) is a humanized monoclonal antibody therapeutic available within the European Union since its licensure in 2005.2 Commercially available as Avastin, manufactured by Roche, BEV is indicated for the treatment of a number of cancers, namely, metastatic colorectal cancer, first-line treatment of advanced nonsquamous nonsmall cell lung cancer, metastatic breast cancer, advanced renal cell carcinoma, and advanced epithelial ovarian, fallopian tube, and primary peritoneal cancers.3 The efficacy of highly selective © 2018 American Chemical Society
target-ligand binding molecules, such as BEV, has paved the way for therapeutic agents with minimal off-target effects, resulting in better treatments with fewer side effects.4 However, with these added advantages have come a number of formulation challenges. Currently, BEV is available as a concentrated solution for infusion and is delivered over 30−90 min, using traditional needle and syringe technology. The vast majority of biotherapeutic antibody drugs like BEV are delivered in a similar way. It has been well documented that one significant drawback to biotherapeutic formulation is the lack of appropriate drug delivery platforms available for Received: Revised: Accepted: Published: 3545
May 23, 2018 July 2, 2018 July 11, 2018 July 11, 2018 DOI: 10.1021/acs.molpharmaceut.8b00544 Mol. Pharmaceutics 2018, 15, 3545−3556
Article
Molecular Pharmaceutics
USA. Cyanoacrylate glue was purchased from Loctite Dublin, Ireland. SpeedMixer, DAC 150 FVZ-K, was purchased from Synergy Devices Ltd., U.K. Virtis Advantage Bench top Freeze Drier System was purchased from SP Scientific, Warminster PA, USA. The patch occlusive (Scotchpak 9523) was purchased from 3M Carrickmines, Ireland. The occlusive layer was fixed to the MN patch using an adhesive (DuroTak 87−2100), which was purchased from National Starch and Chemical Company, Bridgewater, New Jersey, USA. 2.2. Pharmaceutical Analysis of BEV in Vitro and in Vivo. The ELISA employed for the detection and quantification of BEV from in vitro sample matrices and in vivo Sprague−Dawley rat serum matrices was validated in conjunction with the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Validation of Analytical Procedures Q2 Analytical Validation Revision one (R1) 2005. In summary, the primary coating antibody, recombinant human VEGF165, was diluted 1:5000 in 0.1 M bicarbonate buffer (pH 9.6). One hundred microliters of the diluted recombinant human VEGF 165 solution was dispensed into each well, covered with Parafilm and aluminum foil, and incubated for 16 h at 4 °C. The plate was washed with washing buffer, comprising 0.05% v/v Tween-20 in PBS (PBST), and left to soak for 30 s before being discarded. This process was repeated five times, following which the plate was dried briefly using absorbent paper. The plate was then blocked with SuperBlock T20 for 2 h at room temperature. The plate was then washed with PBST, as described previously. A freshly prepared BEV solution at a concentration of 1 mg/mL in PBS was prepared in the range of 400 to 5 ng/mL for in vitro sample analysis and 400 to 50 ng/mL for in vivo sample analysis. Samples were incubated for 1 h and then washed with PBST. The plate was incubated with the secondary antibody, biotinylated VEGF165 antibody, diluted 1:10,000 in SuperBlock T20 buffer for 1 h at room temperature and then washed with PBST. The plate was incubated with streptavidinhorseradish peroxidase (HRP) conjugate, diluted 1:5000 in PBS only, for 30 min at room temperature, and again washed with PBST. The substrate 3,3′,5,5′-tetramethylbenzidine (TMB) was added to each well and incubated for 30 min. Color development was ended using 4.0 M hydrochloric acid, and optical density (OD) was measured at 450 nm using a micro 96-well plate spectrophotometer (Powerwave XS, BioTek Instruments Inc., London, U.K.). Correlation analysis with least-squares linear regression analysis was performed on the calibration curves generated from both analytical methods, enabling determination of the equation of the line and their coefficients of determination. Limits of detection (LoD) and limits of quantification (LoQ) were determined using a method based on the standard deviation of the response and the slope of the representative calibration curve, as described in the guidelines from the ICH.12 The LoD of each method was determined as follows, using eq 1:
biologic drugs. Biotherapeutics are particularly prone to degradation, even under highly controlled environments. Loss of biological activity can arise as a result of structural changes resulting from variation in pH, alterations in ionic and osmotic pressure , and shear stresses exerted on the formulation.5 A number of formulation options have been explored for delivery of monoclonal antibodies, such as pulmonary and nasal delivery. However, these have failed to become widely accepted within the pharmaceutical industry and instead have remained within the realm of curiosity-driven research.6 Similarly, significant costs associated with initial development of biotherapeutic agents, such as BEV, have made these treatment options expensive. As such, this expense has resulted in the need to develop delivery methods that demonstrate high dose-delivery efficiency. Microneedle (MN) technology has emerged as a credible option for transdermal drug delivery of biotherapeutic agents. MN are microdimensional protrusions arranged on a supporting baseplate that can penetrate the skin’s stratum corneum (SC) barrier and provide access for drugs to dermal tissue. A number of research groups have demonstrated successful delivery of drug therapies across the SC and into the dermal microcirculation.7−9 Polymeric MN platforms such as dissolving and hydrogel-forming systems show most promise with respect to delivery of large quantities of drug.10 The delivery of large molecular weight monoclonal antibodies, which are usually required in high doses, requires a strategy capable of providing high dose delivery. This particular issue provides a significant challenge for many of the solid and coated MN technologies, which are usually limited to low dose, potent agents such as vaccines.11 As such, polymeric MN arrays can be used to deliver higher quantities of therapeutic agents. In this work, the aim was to compare and contrast the delivery of BEV using a hydrogel-forming MN platform and, independently, from a dissolving MN platform. This is the first example of a transdermal delivery system compatible with a biotherapeutic macromolecule of this molecular size. This work encompasses the formulation, characterization, and in vitro transdermal permeation of BEV from a hydrogel-forming MN platform and from a dissolving MN platform across excised neonatal porcine skin. Further, these two prototype MN platforms were tested in vivo, in Sprague−Dawley rats assessing the serum concentrations of BEV and tissue concentrations of BEV in lymph nodes, spleen, and skin tissues.
2. MATERIALS AND METHODS 2.1. Chemicals. Avastin concentrate solution for infusion at 25 mg/mL was purchased from Roche, Welwyn Gaden City, Hertfordshire, UK. Cryogel SG3 was supplied by PB Gelatins, Pontypridd, UK. Pearlitol 50C-Mannitol was supplied by Roquette, Lestrem, France. Sucrose was purchased from Sigma-Aldrich, Dorset, U.K. Sodium chloride (NaCl) was purchased from Sigma-Aldrich, Steinheim, Germany. Sodium carbonate (Na2CO3) was purchased from Sigma-Aldrich, Steinheim, Germany. Gantrez S-97 was a gift from Ashland Pharmaceutical, Kidderminster, U.K. PVA (MW 9000−10000 Da) was purchased from Sigma-Aldrich, Steinheim, Germany. Nair Gentle hair removal cream was purchased from Nair Co., London, U.K. Electric hair clippers were bought from Remmington Co., London, U.K. Franz cell apparatus was purchased from Crown Glass Co. Sommerville, New Jersey,
LoD =
3.3σ S
(1)
where σ is the standard deviation of the response data used to construct the regression lines and S is the slope of that line. Subsequently, the LoQ was determined using eq 2: 3546
DOI: 10.1021/acs.molpharmaceut.8b00544 Mol. Pharmaceutics 2018, 15, 3545−3556
Article
Molecular Pharmaceutics LoQ =
10σ S
frozen at −80 °C for a minimum of 60 min and then lyophilized in a freeze-drier according to the following regime: primary drying for 48 h at a shelf temperature of −40 °C, secondary drying for 10 h at a shelf temperature of 20 °C, and vacuum pressure of 50 mTorr. 2.7. Loss of Mass Following Lyophilization of BEV Containing Reservoirs. Low and high dose lyophilized wafers containing BEV were assessed for mass loss, as an indication of water loss following the lyophilization process. Initially, approximately 250 mg of the wet formulation was cast into wafer molds, with the exact mass recorded. Following lyophilization, the wafers were demolded and weighed. Using eq 3, the loss of mass as a percentage was calculated as
(2)
2.3. Stability Studies of BEV in PBS. Standard solutions of BEV (250 μg/mL) in PBS were prepared by diluting BEV in PBS (pH 7.4), and these were stored under various conditions, namely, refrigerated to 4 °C, protected from light and at ambient temperature (20 °C), and exposed to natural light, heated using an incubator to 37 °C, and protected from light. These solutions were stored in 50 mL falcon tubes, and samples were taken at 0, 24, 48, and 72 h. A minimum of three replicates were stored in each case with 1 mL samples taken at each time point. The samples were subject to one complete freeze−thaw cycle prior to analysis by BEV specific ELISA, described below. 2.4. Formulation of Dissolving MN Arrays Containing BEV. Dissolving MN arrays were prepared from aqueous blends of PVA and Avastin concentrate solution for infusion. Initially an aqueous stock solution of PVA was prepared at 40% w/w. The PVA powder was mixed with water in a water bath at 40 °C for 3 h, following which the formulation was allowed to stand for 12 h. The PVA stock solution was diluted with BEV and distilled water to achieve a working concentration of 20% w/w PVA. This formulation was slowly mixed with a glass rod to ensure minimal bubble formation and then centrifuged at 3500 rpm for 2 min. The formulation was dispensed onto prefabricated silicone molds using a 1 mL standard syringe. The silicone molds had an array of 19 × 19 pyramidal needles, each 500 μm high and 300 μm at the base with an interspacing of 50 μm. Gel formulation (100 μL) was dispensed onto each mold. Following this, the molds were placed into a stainless steel positive pressure chamber, and air was pumped into the vessel to increase atmospheric pressure to 3 bar. This pressure was maintained for 15 min to facilitate filling of the needle tips, the pressure was then reduced to normal atmospheric pressure, and the molds were removed from the chamber and allowed to dry at room temperature for 48 h. The dissolving MN arrays were then removed from the molds, ready for use. 2.5. Formulation of Hydrogel-Forming MN Arrays. Hydrogel-forming MN arrays were formulated from 20% w/w Gantrez S-97, 7.5% w/w PEG 10,000, and 3% w/w Na2CO3. First, an aqueous blend was obtained by fully dissolving Gantrez S-97 and PEG 10,000 in water; following this, Na2CO3 was added. This formulation was mixed well using a glass rod until foaming had ceased and a uniform gel was obtained. The formulation was then transferred into 50 mL falcon tubes and centrifuged for 15 min at 3500 rpm to remove bubbles. The formulation was dispensed onto prefabricated silicone molds as described above. The hydrogel-forming MN arrays were cross-linked through an esterification reaction, by heating at 80 °C for a further 24 h.13−15 2.6. Formulation of Lyophilized Reservoirs Containing BEV. Lyophilized drug reservoirs loaded individually with BEV were prepared following a previously developed lyophilization process.14 Briefly, BEV-containing reservoirs were formulated with 20% w/w Avastin concentrate solution for infusion (25 mg/mL BEV) dissolved in distilled water. This was then added to a mixture containing 10% w/w gelatin, 40% w/w mannitol, 10% w/w NaCl, and 1% w/w sucrose yielding a final mixture with 0.5% w/w BEV. The formulation was then mixed by a speed-mixer at 3000 rpm for 60 s and sonicated at 37 °C for 60 min. The resulting formulation was then cast into 13 mm radius cylindrical molds (250 mg) with one open end,
loss of mass(%) =
M w − Md × 100 Mw
(3)
where Mw is the mass of wet formulation cast into the wafer molds and Md is the mass of the dry wafer following lyophilization. 2.8. MN Insertion Studies. Parafilm was used as a model membrane to assess MN strength for penetration into the skin, as described previously by our group.15 Briefly, one sheet of Parafilm was carefully folded, such that it formed eight layers, approximately 1 mm thick. This was then laid onto a poly(ethylene) sheet for support. Manual insertion studies were conducted by applying thumb pressure to the MN array formulations. MN depth of penetration was assessed through visual inspection of the Parafilm layers. 2.9. BEV Recovery from Lyophilized Reservoirs. Low and high dose lyophilized wafers containing BEV were dissolved fully in 10 mL of PBS (pH 7.4). A magnetic stirrer was used to ensure complete mixing, with the rotor set at 200 rpm, 20 °C for 30 min. Following complete dissolution, samples were taken and analyzed using the BEV specific ELISA. 2.10. BEV Recovery from PVA Dissolving MN. PVA MN arrays containing BEV were dissolved in 10 mL of PBS (pH 7.4). A magnetic stirrer was used to ensure complete mixing, with the rotor set at 200 rpm, 20 °C for 30 min. Following complete dissolution, samples were taken and analyzed using BEV specific ELISA. 2.11. BEV MN Mass. PVA MN arrays containing BEV were formulated, and dry mass was recorded. The needle tips were then removed using a scalpel blade, and baseplate mass was recorded. The needle mass was calculated by subtracting the mass of arrays without needles from the mass of arrays with needles. 2.12. In Vitro Permeation Studies of BEV on Modified Franz Cell Apparatus. The permeation of BEV from lyophilized wafers though swelling hydrogel MN arrays and subsequently across neonatal porcine skin was investigated in vitro using modified Franz cell apparatus. FDC-400 Franz diffusion cells with flat flange, 15 mm luminal diameter, mounted on a FDCD diffusion drive console providing synchronized stirring at 600 rpm, and receiver compartment temperature regulated at 37 ± 1 °C were used in this experimentation, as described previously.16 Neonatal porcine skin was acquired from stillborn piglets and excised immediately (
